Sun Salutations (Surya Namaskar) is one of the fundamentals of a solid yoga practice, and can actually be a complete practice in and of itself. There are about 12 poses linked in a flowing series that lengthens and strengthens the body. There are many sun salutation variations, but the important common denominator between each one is that they all help gather the strength of the mind and aids in mental focus. Without bringing the mind to a state in which it can push the body through the various stages of yoga practice, say texts of old, yoga practitioners are more susceptible to injury. For people with lower back or tight hip problems (runners and cycles), the lunge salute works the best, giving increased flexibility, space and length to the lower back. The lunge also stretches the musculature of the upper and inner thighs while also stimulating the stomach, spleen, and liver meridians.
The cycle goes as follows: stand strong with both legs rooted into the ground (Tadasana or Mountain Pose), find the center of your breath, alignment, and balance. Inhale and reach up (metaphorically kissing the sun, representing our source of sustenance as well as the light within that burns continuously for awakening). Exhale and fold down to Uttanasana (Standing Forward Bend), bowing to the earth, while stretching the hamstrings, calf muscles, and lower back. Inhale, keeping the hands down, and lift the chest. Exhale and step the right foot back and lower the back knee and foot down into a low lunge. 
In the lunge, inhale and lift the arms up; keep the left buttocks strong while slightly hugging in the inner groins toward each other. Keep the neck in neutral as you look forward. Stay for five breaths, then exhale and lower the arms. Inhale and step the left foot back into Plank Pose (both hands under the shoulders, arms, and legs straight), and then exhale and lower to Chaturanga Dandasana (Four-Limbed Staff Pose) with legs straight or knees on the ground to strengthen the arms and trapezius, drawing the belly back as you lower. Lower the pelvis, tuck the toes and inhale as you lift the chest and legs in Salabhasana (Locust Pose), strengthening the lower back. Alternate between having the legs together and bringing them apart from each round. Stay in Salabhasana for five breaths. Exhale and lower the feet and head. Inhale up to Plank, and exhale to Adho Mukha Svanasana (Downward-Facing Dog Pose), lengthening the hamstrings, calves, and torso, while strengthening the upper body.
After five breaths inhale and step the right foot forward into a lunge on the other side. Exhale there. Then inhale and lift the arms for five breaths. On the fifth exhalation, lower the arms, and on the inhalation, step the back foot forward to meet the front one. Lift the chest and exhale; fold into Uttanasana (Standing Forward Bend).
On the next inhalation, lift the arms, leading from the sternum, and come up to standing (bend the knees if the lower back is weak). Exhale, standing tall with the hands in Namaste, or Prayer. Close your eyes. Feel your beating heart. Your breath. The energy (prana).
Please note that "Sūryānamaskāra B" is also a Sun Salutation, but is a little more vigorous and weaves the warrior postures into a flowing sequence with the breath. The added movement increases the physical heat in the body creating an ideal environment for the following asanas.
Try repeating this flow five to seven rounds each morning before you go to work, start your day, or in the evening before settling into your evening routine. Incorporating Sun Salutations regularly can allow your yoga practice stronger and you, a more aware and conscious, vibrant being.
